GB2058692A

GB2058692A - Anti-starvation device for vehicle fuel tank

Info

Publication number: GB2058692A
Application number: GB8027284A
Authority: GB
Original assignee: Rover Co Ltd
Current assignee: Rover Co Ltd
Priority date: 1979-08-21
Filing date: 1980-08-21
Publication date: 1981-04-15
Also published as: GB2058692B

Abstract

An anti-starvation device 11 for vehicle fuel tank 21 is deformable to enable it to be placed in the fuel tank through a relatively small aperture 20 and then expanded to increase its capacity once inside the fuel tank. This enables an anti-starvation device of adequate capacity to be used in plastics fuel tanks which provide access to their interiors only through relatively small apertures adapted to receive fuel level measuring units etc. The device 11 is formed of plastics material and includes a relatively rigid base portion just small enough to pass through the aperture 20, and a flexible upper portion 14 provided with fold lines which promote the formation of a series of pleats when the device is subjected to radially inward pressure. The device 11 is fixed in position in the tank by ultrasonic welding, friction welding or adhesive. <IMAGE>

Description

SPECIFICATION Anti-starvation devices This invention relates to so-called antistarvation devices, which are commonly fitted to fuel tanks for vehicles to retain fuel at the take-off point in the tank when the fuel is urged away from that point due to vehicle movement.

Hitherto such devices have commonly comprised a weir or labyrinth arrangement around the open end of a take-off pipe, which prevents the fuel flowing away from the pipe end when the vehicle is decelerating or accelerating, for example, thereby ensuring that the pipe end remains immersed and the fuel supply is uninterrupted. Clearly, to be effective such devices must contain a sufficient volume of fuel to maintain the continuity of supply over the longest period for which the fuel will be urged away from the pipe end. While this presents no problem in the case of a metal tank comprised of two parts wherein the anti-starvation device can be secured in one part before the two are joined, in the case of a single piece tank, of blow moulded plastics for example, the device must be inserted through a hole in the shell.Since the hole must be closed after the anti-starvation device has been inserted, it is generally desirable to have as small a hole as possible so as to reduce the size of closure member necessary - a compromise must be struck however to permit a sufficient size of antistarvation device to be used.

According to the present invention there is provided an anti-starvation device for a vehicle fuel tank having a folding substantially impermeable wall whereby the device may be passed through an aperture in a fuel tank in a folded condition, and thereafter expanded to increase its effective capacity.

An embodiment will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a side elevation of an anti-starvation device in accordance with the invention; Figure 2 is a plan view of part of the device of Figure 1; and Figure 3 shows the anti-starvation device of Figure 1 both during insertion into a blow moulded plastics fuel tank and (in phantom) in its final position in the tank.

As shown in Figures 1 and 2 an anti-starvation device 11 for a vehicle fuel tank comprises a cylindrical wall portion 12 closed at one end by a disc shaped base 1 3 and extended at its other end by an upper generally frusto-conical wall portion 14 which is open at its upper end remote from the base 1 3. The wall portions and base are impermeable except for a hole 1 5 in wall portion 1 2 adjacent the base 13 which provides for a restricted flow of fluid into or out of the device.

The upper wail portion 14 is provided with a series of fold lines, whereby when the wall portion is subjected to pressure radially inwardly toward the principal axis X-X, it forms into a series of pleats 16. Each pleat 1 6 comprises a substantially triangular piece 1 7 which folds about its base where it is connected to wall portion 12, and a pair of inverted triangular pieces 1 8 which flank the piece 1 7 and fold inwardly relative thereto.

The device 11 is formed of plastics material with the base and lower wall portion 12 being of thicker material and hence more rigid than the upper wall portion 14.

Figure 3 shows the device 11 mounted on an ultrasonic horn by a flange 19 which is an interference fit in the inside of lower wall portion 12. The device is shown in full being inserted through an aperture 20 in a blow moulded plastics fuel tank 21. Aperture 20 serves to mount a conventional tank unit in use of the tank, including a fuel take-off pipe which extends vertically down into the tank to draw off fuel from the interior of the device 11, and a float and arm which sense the fluid level in the tank.

The diameter of aperture 20 is only slightly greater than that of the base 13, and hence is substantially smaller than the normal diameter of the upper wall portion 14. If a non-folding upper portion were used it would therefore be restricted to a substantially smaller diameter than that of the present invention, with a resultant loss in capacity of the device. In the case of the illustrated device however, the upper portion is automatically contracted as it slides through the aperture, to spring back to its normal position (shown in phantom in Figure 3) when it is wholly within the fuel tank, to increase its average plan crosssectioned area, and hence its capacity. The device is then located on the base of the fuel tank, where it is uitrasonically welded in place.

In use fuel floods the device, either by spilling over the top of the upper portion or through the hold 15, and is drawn off by a pipe (not shown) whose end is located within the lower portion 1 2.

When the fuel is subjected to harsh acceleration, for example when the vehicle in which the tank is mounted is cornered rapidly, fuel in the tank may be forced to the side of the tank remote from the take-off pipe. Fuel contained within the device 11 will be retained around the pipe however by walls of the device, and while some fuel will drain out of hole 15, the rate will not be sufficient to interrupt continuity of supply before the acceleration has ceased and the bulk of the fuel has returned to surround the device 11 once more.

Whilst the increased capacity obtained by using a folding upper wall portion is a primary benefit, the shape of the device is also beneficial. By having a relatively small plan cross-sectioned area at the base compared to that above, fuel is constrained longer at the take-off point than would be the case with say a cylindrical device of equal height and capacity - that is to say with a larger base area.

It will be clear that numerous variations from the illustrated arrangement are possible. For example the shape of the device and the manner of folding can be varied, as can the number and position of bleed holes such as 1 5. Indeed, an arrangement can be envisaged in which the upper and/or the lower wall portions are slightly permeable to enable the device to fill with fuel whilst remaining substantially impermeable so far as concerns any significant loss of fuel from the device over a typical time scale for which fuel is likely to be urged away from the take-off point.

Whilst the illustrated arrangement shows the device being ultrasonically welded in place, other means of attachment such as friction welding, or adhesives could be employed. Moreover whilst the device is particularly suited to solving the problems of plastics tanks, it could of course be used in a metal tank if so desired.

Claims

1. An anti-starvation device for retaining fuel in a vehicle fuel tank adjacent a fuel outlet, characterised by a substantially impermeable wall (14) of variable dimensions whereby the device may be passed through an aperture (20) in a fuel tank in a contracted state, and thereafter expanded to increase its effective capacity, the device is being arranged to permit limited fluid flow past the wall.

2. A device as claimed in claim 1, characterised in that said limited fluid flow is permitted by an aperture 115) in said device.

3. A device as claimed in claim 1 or 2, characterised in that fluid flow is permitted by means of a porosity in a wall of said device.

4. A device as claimed in claim 1, 2 or 3, characterised in that said limited fluid flow is permitted by a labyrinth arrangement of the walls of said device.

5. A device as claimed in any preceding claim, characterised in that said wall has a purality of predetermined folds.

6. A device as claimed in any preceding claim, characterised in that said device 1) is arranged to contract as a result of contact with the edges of the aperture through which it passes.

7. A device as claimed in any preceding claim, characterised in that said wall (14) flares outwardly from a base portion (12, 13) of the device in the expanded condition thereof.

8. A device as claimed in any preceding claim, characterised in that the device is made of a resilient material whereby the device expands from its folded state.

9. A fuel tank characterised in that it incorporates an anti-starvation device (11) according to any preceding claim.

10. A fuel tank as claimed in claim 9, characterised in that the tank (21) is of moulded plastics material and said anti-starvation device (11) is glued or welded to an interior surface thereof.

11. A method of producing a fuel tank having an anti-starvation device, charaterised by the step of inserting said device (11) in a contracted state through an aperture (20) in said tank (21) and having said device assume an expanded state with increased capacity when the device is located in the tank.

12. A method as claimed in claim 11, characterised by the step of producing said tank (21) as a one piece moulding in plastics.

13. A method as claimed in claim 11 or 12, characterised by the step of welding or gluing said device (11) in place in said tank (21).

14. A method as claimed in claim 1 1, 12 or 13, characterised in that said anti-starvation device (11) contracts during insertion into the tank (21) as a result of contact with the edge of said aperture (20).